Javascript Spy on object method. Keeps the arguments of each call and can be later destroyed

SimpleSpy.js

function Spy (object, method) {
  var original = object[method];
  var spy = {
    calls: [],
    destroy: function () {
      object[method] = original;
    }
  };
  object[method] = function () {
    var args = Array.prototype.slice.call(arguments);
    spy.calls.push(args);
    original.apply(object, args);
  };
  object[method].prototype = original.prototype;
  return spy;
}